xref: /openbmc/linux/fs/nfs/nfs2xdr.c (revision 5a0e3ad6)
1 /*
2  * linux/fs/nfs/nfs2xdr.c
3  *
4  * XDR functions to encode/decode NFS RPC arguments and results.
5  *
6  * Copyright (C) 1992, 1993, 1994  Rick Sladkey
7  * Copyright (C) 1996 Olaf Kirch
8  * 04 Aug 1998  Ion Badulescu <ionut@cs.columbia.edu>
9  * 		FIFO's need special handling in NFSv2
10  */
11 
12 #include <linux/param.h>
13 #include <linux/time.h>
14 #include <linux/mm.h>
15 #include <linux/errno.h>
16 #include <linux/string.h>
17 #include <linux/in.h>
18 #include <linux/pagemap.h>
19 #include <linux/proc_fs.h>
20 #include <linux/sunrpc/clnt.h>
21 #include <linux/nfs.h>
22 #include <linux/nfs2.h>
23 #include <linux/nfs_fs.h>
24 #include "internal.h"
25 
26 #define NFSDBG_FACILITY		NFSDBG_XDR
27 
28 /* Mapping from NFS error code to "errno" error code. */
29 #define errno_NFSERR_IO		EIO
30 
31 /*
32  * Declare the space requirements for NFS arguments and replies as
33  * number of 32bit-words
34  */
35 #define NFS_fhandle_sz		(8)
36 #define NFS_sattr_sz		(8)
37 #define NFS_filename_sz		(1+(NFS2_MAXNAMLEN>>2))
38 #define NFS_path_sz		(1+(NFS2_MAXPATHLEN>>2))
39 #define NFS_fattr_sz		(17)
40 #define NFS_info_sz		(5)
41 #define NFS_entry_sz		(NFS_filename_sz+3)
42 
43 #define NFS_diropargs_sz	(NFS_fhandle_sz+NFS_filename_sz)
44 #define NFS_removeargs_sz	(NFS_fhandle_sz+NFS_filename_sz)
45 #define NFS_sattrargs_sz	(NFS_fhandle_sz+NFS_sattr_sz)
46 #define NFS_readlinkargs_sz	(NFS_fhandle_sz)
47 #define NFS_readargs_sz		(NFS_fhandle_sz+3)
48 #define NFS_writeargs_sz	(NFS_fhandle_sz+4)
49 #define NFS_createargs_sz	(NFS_diropargs_sz+NFS_sattr_sz)
50 #define NFS_renameargs_sz	(NFS_diropargs_sz+NFS_diropargs_sz)
51 #define NFS_linkargs_sz		(NFS_fhandle_sz+NFS_diropargs_sz)
52 #define NFS_symlinkargs_sz	(NFS_diropargs_sz+1+NFS_sattr_sz)
53 #define NFS_readdirargs_sz	(NFS_fhandle_sz+2)
54 
55 #define NFS_attrstat_sz		(1+NFS_fattr_sz)
56 #define NFS_diropres_sz		(1+NFS_fhandle_sz+NFS_fattr_sz)
57 #define NFS_readlinkres_sz	(2)
58 #define NFS_readres_sz		(1+NFS_fattr_sz+1)
59 #define NFS_writeres_sz         (NFS_attrstat_sz)
60 #define NFS_stat_sz		(1)
61 #define NFS_readdirres_sz	(1)
62 #define NFS_statfsres_sz	(1+NFS_info_sz)
63 
64 /*
65  * Common NFS XDR functions as inlines
66  */
67 static inline __be32 *
68 xdr_encode_fhandle(__be32 *p, const struct nfs_fh *fhandle)
69 {
70 	memcpy(p, fhandle->data, NFS2_FHSIZE);
71 	return p + XDR_QUADLEN(NFS2_FHSIZE);
72 }
73 
74 static inline __be32 *
75 xdr_decode_fhandle(__be32 *p, struct nfs_fh *fhandle)
76 {
77 	/* NFSv2 handles have a fixed length */
78 	fhandle->size = NFS2_FHSIZE;
79 	memcpy(fhandle->data, p, NFS2_FHSIZE);
80 	return p + XDR_QUADLEN(NFS2_FHSIZE);
81 }
82 
83 static inline __be32*
84 xdr_encode_time(__be32 *p, struct timespec *timep)
85 {
86 	*p++ = htonl(timep->tv_sec);
87 	/* Convert nanoseconds into microseconds */
88 	*p++ = htonl(timep->tv_nsec ? timep->tv_nsec / 1000 : 0);
89 	return p;
90 }
91 
92 static inline __be32*
93 xdr_encode_current_server_time(__be32 *p, struct timespec *timep)
94 {
95 	/*
96 	 * Passing the invalid value useconds=1000000 is a
97 	 * Sun convention for "set to current server time".
98 	 * It's needed to make permissions checks for the
99 	 * "touch" program across v2 mounts to Solaris and
100 	 * Irix boxes work correctly. See description of
101 	 * sattr in section 6.1 of "NFS Illustrated" by
102 	 * Brent Callaghan, Addison-Wesley, ISBN 0-201-32750-5
103 	 */
104 	*p++ = htonl(timep->tv_sec);
105 	*p++ = htonl(1000000);
106 	return p;
107 }
108 
109 static inline __be32*
110 xdr_decode_time(__be32 *p, struct timespec *timep)
111 {
112 	timep->tv_sec = ntohl(*p++);
113 	/* Convert microseconds into nanoseconds */
114 	timep->tv_nsec = ntohl(*p++) * 1000;
115 	return p;
116 }
117 
118 static __be32 *
119 xdr_decode_fattr(__be32 *p, struct nfs_fattr *fattr)
120 {
121 	u32 rdev, type;
122 	type = ntohl(*p++);
123 	fattr->mode = ntohl(*p++);
124 	fattr->nlink = ntohl(*p++);
125 	fattr->uid = ntohl(*p++);
126 	fattr->gid = ntohl(*p++);
127 	fattr->size = ntohl(*p++);
128 	fattr->du.nfs2.blocksize = ntohl(*p++);
129 	rdev = ntohl(*p++);
130 	fattr->du.nfs2.blocks = ntohl(*p++);
131 	fattr->fsid.major = ntohl(*p++);
132 	fattr->fsid.minor = 0;
133 	fattr->fileid = ntohl(*p++);
134 	p = xdr_decode_time(p, &fattr->atime);
135 	p = xdr_decode_time(p, &fattr->mtime);
136 	p = xdr_decode_time(p, &fattr->ctime);
137 	fattr->valid |= NFS_ATTR_FATTR_V2;
138 	fattr->rdev = new_decode_dev(rdev);
139 	if (type == NFCHR && rdev == NFS2_FIFO_DEV) {
140 		fattr->mode = (fattr->mode & ~S_IFMT) | S_IFIFO;
141 		fattr->rdev = 0;
142 	}
143 	return p;
144 }
145 
146 static inline __be32 *
147 xdr_encode_sattr(__be32 *p, struct iattr *attr)
148 {
149 	const __be32 not_set = __constant_htonl(0xFFFFFFFF);
150 
151 	*p++ = (attr->ia_valid & ATTR_MODE) ? htonl(attr->ia_mode) : not_set;
152 	*p++ = (attr->ia_valid & ATTR_UID) ? htonl(attr->ia_uid) : not_set;
153 	*p++ = (attr->ia_valid & ATTR_GID) ? htonl(attr->ia_gid) : not_set;
154 	*p++ = (attr->ia_valid & ATTR_SIZE) ? htonl(attr->ia_size) : not_set;
155 
156 	if (attr->ia_valid & ATTR_ATIME_SET) {
157 		p = xdr_encode_time(p, &attr->ia_atime);
158 	} else if (attr->ia_valid & ATTR_ATIME) {
159 		p = xdr_encode_current_server_time(p, &attr->ia_atime);
160 	} else {
161 		*p++ = not_set;
162 		*p++ = not_set;
163 	}
164 
165 	if (attr->ia_valid & ATTR_MTIME_SET) {
166 		p = xdr_encode_time(p, &attr->ia_mtime);
167 	} else if (attr->ia_valid & ATTR_MTIME) {
168 		p = xdr_encode_current_server_time(p, &attr->ia_mtime);
169 	} else {
170 		*p++ = not_set;
171 		*p++ = not_set;
172 	}
173   	return p;
174 }
175 
176 /*
177  * NFS encode functions
178  */
179 /*
180  * Encode file handle argument
181  * GETATTR, READLINK, STATFS
182  */
183 static int
184 nfs_xdr_fhandle(struct rpc_rqst *req, __be32 *p, struct nfs_fh *fh)
185 {
186 	p = xdr_encode_fhandle(p, fh);
187 	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
188 	return 0;
189 }
190 
191 /*
192  * Encode SETATTR arguments
193  */
194 static int
195 nfs_xdr_sattrargs(struct rpc_rqst *req, __be32 *p, struct nfs_sattrargs *args)
196 {
197 	p = xdr_encode_fhandle(p, args->fh);
198 	p = xdr_encode_sattr(p, args->sattr);
199 	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
200 	return 0;
201 }
202 
203 /*
204  * Encode directory ops argument
205  * LOOKUP, RMDIR
206  */
207 static int
208 nfs_xdr_diropargs(struct rpc_rqst *req, __be32 *p, struct nfs_diropargs *args)
209 {
210 	p = xdr_encode_fhandle(p, args->fh);
211 	p = xdr_encode_array(p, args->name, args->len);
212 	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
213 	return 0;
214 }
215 
216 /*
217  * Encode REMOVE argument
218  */
219 static int
220 nfs_xdr_removeargs(struct rpc_rqst *req, __be32 *p, const struct nfs_removeargs *args)
221 {
222 	p = xdr_encode_fhandle(p, args->fh);
223 	p = xdr_encode_array(p, args->name.name, args->name.len);
224 	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
225 	return 0;
226 }
227 
228 /*
229  * Arguments to a READ call. Since we read data directly into the page
230  * cache, we also set up the reply iovec here so that iov[1] points
231  * exactly to the page we want to fetch.
232  */
233 static int
234 nfs_xdr_readargs(struct rpc_rqst *req, __be32 *p, struct nfs_readargs *args)
235 {
236 	struct rpc_auth	*auth = req->rq_task->tk_msg.rpc_cred->cr_auth;
237 	unsigned int replen;
238 	u32 offset = (u32)args->offset;
239 	u32 count = args->count;
240 
241 	p = xdr_encode_fhandle(p, args->fh);
242 	*p++ = htonl(offset);
243 	*p++ = htonl(count);
244 	*p++ = htonl(count);
245 	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
246 
247 	/* Inline the page array */
248 	replen = (RPC_REPHDRSIZE + auth->au_rslack + NFS_readres_sz) << 2;
249 	xdr_inline_pages(&req->rq_rcv_buf, replen,
250 			 args->pages, args->pgbase, count);
251 	req->rq_rcv_buf.flags |= XDRBUF_READ;
252 	return 0;
253 }
254 
255 /*
256  * Decode READ reply
257  */
258 static int
259 nfs_xdr_readres(struct rpc_rqst *req, __be32 *p, struct nfs_readres *res)
260 {
261 	struct kvec *iov = req->rq_rcv_buf.head;
262 	size_t hdrlen;
263 	u32 count, recvd;
264 	int status;
265 
266 	if ((status = ntohl(*p++)))
267 		return nfs_stat_to_errno(status);
268 	p = xdr_decode_fattr(p, res->fattr);
269 
270 	count = ntohl(*p++);
271 	res->eof = 0;
272 	hdrlen = (u8 *) p - (u8 *) iov->iov_base;
273 	if (iov->iov_len < hdrlen) {
274 		dprintk("NFS: READ reply header overflowed:"
275 				"length %Zu > %Zu\n", hdrlen, iov->iov_len);
276 		return -errno_NFSERR_IO;
277 	} else if (iov->iov_len != hdrlen) {
278 		dprintk("NFS: READ header is short. iovec will be shifted.\n");
279 		xdr_shift_buf(&req->rq_rcv_buf, iov->iov_len - hdrlen);
280 	}
281 
282 	recvd = req->rq_rcv_buf.len - hdrlen;
283 	if (count > recvd) {
284 		dprintk("NFS: server cheating in read reply: "
285 			"count %u > recvd %u\n", count, recvd);
286 		count = recvd;
287 	}
288 
289 	dprintk("RPC:      readres OK count %u\n", count);
290 	if (count < res->count)
291 		res->count = count;
292 
293 	return count;
294 }
295 
296 
297 /*
298  * Write arguments. Splice the buffer to be written into the iovec.
299  */
300 static int
301 nfs_xdr_writeargs(struct rpc_rqst *req, __be32 *p, struct nfs_writeargs *args)
302 {
303 	struct xdr_buf *sndbuf = &req->rq_snd_buf;
304 	u32 offset = (u32)args->offset;
305 	u32 count = args->count;
306 
307 	p = xdr_encode_fhandle(p, args->fh);
308 	*p++ = htonl(offset);
309 	*p++ = htonl(offset);
310 	*p++ = htonl(count);
311 	*p++ = htonl(count);
312 	sndbuf->len = xdr_adjust_iovec(sndbuf->head, p);
313 
314 	/* Copy the page array */
315 	xdr_encode_pages(sndbuf, args->pages, args->pgbase, count);
316 	sndbuf->flags |= XDRBUF_WRITE;
317 	return 0;
318 }
319 
320 /*
321  * Encode create arguments
322  * CREATE, MKDIR
323  */
324 static int
325 nfs_xdr_createargs(struct rpc_rqst *req, __be32 *p, struct nfs_createargs *args)
326 {
327 	p = xdr_encode_fhandle(p, args->fh);
328 	p = xdr_encode_array(p, args->name, args->len);
329 	p = xdr_encode_sattr(p, args->sattr);
330 	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
331 	return 0;
332 }
333 
334 /*
335  * Encode RENAME arguments
336  */
337 static int
338 nfs_xdr_renameargs(struct rpc_rqst *req, __be32 *p, struct nfs_renameargs *args)
339 {
340 	p = xdr_encode_fhandle(p, args->fromfh);
341 	p = xdr_encode_array(p, args->fromname, args->fromlen);
342 	p = xdr_encode_fhandle(p, args->tofh);
343 	p = xdr_encode_array(p, args->toname, args->tolen);
344 	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
345 	return 0;
346 }
347 
348 /*
349  * Encode LINK arguments
350  */
351 static int
352 nfs_xdr_linkargs(struct rpc_rqst *req, __be32 *p, struct nfs_linkargs *args)
353 {
354 	p = xdr_encode_fhandle(p, args->fromfh);
355 	p = xdr_encode_fhandle(p, args->tofh);
356 	p = xdr_encode_array(p, args->toname, args->tolen);
357 	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
358 	return 0;
359 }
360 
361 /*
362  * Encode SYMLINK arguments
363  */
364 static int
365 nfs_xdr_symlinkargs(struct rpc_rqst *req, __be32 *p, struct nfs_symlinkargs *args)
366 {
367 	struct xdr_buf *sndbuf = &req->rq_snd_buf;
368 	size_t pad;
369 
370 	p = xdr_encode_fhandle(p, args->fromfh);
371 	p = xdr_encode_array(p, args->fromname, args->fromlen);
372 	*p++ = htonl(args->pathlen);
373 	sndbuf->len = xdr_adjust_iovec(sndbuf->head, p);
374 
375 	xdr_encode_pages(sndbuf, args->pages, 0, args->pathlen);
376 
377 	/*
378 	 * xdr_encode_pages may have added a few bytes to ensure the
379 	 * pathname ends on a 4-byte boundary.  Start encoding the
380 	 * attributes after the pad bytes.
381 	 */
382 	pad = sndbuf->tail->iov_len;
383 	if (pad > 0)
384 		p++;
385 	p = xdr_encode_sattr(p, args->sattr);
386 	sndbuf->len += xdr_adjust_iovec(sndbuf->tail, p) - pad;
387 	return 0;
388 }
389 
390 /*
391  * Encode arguments to readdir call
392  */
393 static int
394 nfs_xdr_readdirargs(struct rpc_rqst *req, __be32 *p, struct nfs_readdirargs *args)
395 {
396 	struct rpc_task	*task = req->rq_task;
397 	struct rpc_auth	*auth = task->tk_msg.rpc_cred->cr_auth;
398 	unsigned int replen;
399 	u32 count = args->count;
400 
401 	p = xdr_encode_fhandle(p, args->fh);
402 	*p++ = htonl(args->cookie);
403 	*p++ = htonl(count); /* see above */
404 	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
405 
406 	/* Inline the page array */
407 	replen = (RPC_REPHDRSIZE + auth->au_rslack + NFS_readdirres_sz) << 2;
408 	xdr_inline_pages(&req->rq_rcv_buf, replen, args->pages, 0, count);
409 	return 0;
410 }
411 
412 /*
413  * Decode the result of a readdir call.
414  * We're not really decoding anymore, we just leave the buffer untouched
415  * and only check that it is syntactically correct.
416  * The real decoding happens in nfs_decode_entry below, called directly
417  * from nfs_readdir for each entry.
418  */
419 static int
420 nfs_xdr_readdirres(struct rpc_rqst *req, __be32 *p, void *dummy)
421 {
422 	struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
423 	struct kvec *iov = rcvbuf->head;
424 	struct page **page;
425 	size_t hdrlen;
426 	unsigned int pglen, recvd;
427 	u32 len;
428 	int status, nr = 0;
429 	__be32 *end, *entry, *kaddr;
430 
431 	if ((status = ntohl(*p++)))
432 		return nfs_stat_to_errno(status);
433 
434 	hdrlen = (u8 *) p - (u8 *) iov->iov_base;
435 	if (iov->iov_len < hdrlen) {
436 		dprintk("NFS: READDIR reply header overflowed:"
437 				"length %Zu > %Zu\n", hdrlen, iov->iov_len);
438 		return -errno_NFSERR_IO;
439 	} else if (iov->iov_len != hdrlen) {
440 		dprintk("NFS: READDIR header is short. iovec will be shifted.\n");
441 		xdr_shift_buf(rcvbuf, iov->iov_len - hdrlen);
442 	}
443 
444 	pglen = rcvbuf->page_len;
445 	recvd = rcvbuf->len - hdrlen;
446 	if (pglen > recvd)
447 		pglen = recvd;
448 	page = rcvbuf->pages;
449 	kaddr = p = kmap_atomic(*page, KM_USER0);
450 	end = (__be32 *)((char *)p + pglen);
451 	entry = p;
452 
453 	/* Make sure the packet actually has a value_follows and EOF entry */
454 	if ((entry + 1) > end)
455 		goto short_pkt;
456 
457 	for (; *p++; nr++) {
458 		if (p + 2 > end)
459 			goto short_pkt;
460 		p++; /* fileid */
461 		len = ntohl(*p++);
462 		p += XDR_QUADLEN(len) + 1;	/* name plus cookie */
463 		if (len > NFS2_MAXNAMLEN) {
464 			dprintk("NFS: giant filename in readdir (len 0x%x)!\n",
465 						len);
466 			goto err_unmap;
467 		}
468 		if (p + 2 > end)
469 			goto short_pkt;
470 		entry = p;
471 	}
472 
473 	/*
474 	 * Apparently some server sends responses that are a valid size, but
475 	 * contain no entries, and have value_follows==0 and EOF==0. For
476 	 * those, just set the EOF marker.
477 	 */
478 	if (!nr && entry[1] == 0) {
479 		dprintk("NFS: readdir reply truncated!\n");
480 		entry[1] = 1;
481 	}
482  out:
483 	kunmap_atomic(kaddr, KM_USER0);
484 	return nr;
485  short_pkt:
486 	/*
487 	 * When we get a short packet there are 2 possibilities. We can
488 	 * return an error, or fix up the response to look like a valid
489 	 * response and return what we have so far. If there are no
490 	 * entries and the packet was short, then return -EIO. If there
491 	 * are valid entries in the response, return them and pretend that
492 	 * the call was successful, but incomplete. The caller can retry the
493 	 * readdir starting at the last cookie.
494 	 */
495 	entry[0] = entry[1] = 0;
496 	if (!nr)
497 		nr = -errno_NFSERR_IO;
498 	goto out;
499 err_unmap:
500 	nr = -errno_NFSERR_IO;
501 	goto out;
502 }
503 
504 __be32 *
505 nfs_decode_dirent(__be32 *p, struct nfs_entry *entry, int plus)
506 {
507 	if (!*p++) {
508 		if (!*p)
509 			return ERR_PTR(-EAGAIN);
510 		entry->eof = 1;
511 		return ERR_PTR(-EBADCOOKIE);
512 	}
513 
514 	entry->ino	  = ntohl(*p++);
515 	entry->len	  = ntohl(*p++);
516 	entry->name	  = (const char *) p;
517 	p		 += XDR_QUADLEN(entry->len);
518 	entry->prev_cookie	  = entry->cookie;
519 	entry->cookie	  = ntohl(*p++);
520 	entry->eof	  = !p[0] && p[1];
521 
522 	return p;
523 }
524 
525 /*
526  * NFS XDR decode functions
527  */
528 /*
529  * Decode simple status reply
530  */
531 static int
532 nfs_xdr_stat(struct rpc_rqst *req, __be32 *p, void *dummy)
533 {
534 	int	status;
535 
536 	if ((status = ntohl(*p++)) != 0)
537 		status = nfs_stat_to_errno(status);
538 	return status;
539 }
540 
541 /*
542  * Decode attrstat reply
543  * GETATTR, SETATTR, WRITE
544  */
545 static int
546 nfs_xdr_attrstat(struct rpc_rqst *req, __be32 *p, struct nfs_fattr *fattr)
547 {
548 	int	status;
549 
550 	if ((status = ntohl(*p++)))
551 		return nfs_stat_to_errno(status);
552 	xdr_decode_fattr(p, fattr);
553 	return 0;
554 }
555 
556 /*
557  * Decode diropres reply
558  * LOOKUP, CREATE, MKDIR
559  */
560 static int
561 nfs_xdr_diropres(struct rpc_rqst *req, __be32 *p, struct nfs_diropok *res)
562 {
563 	int	status;
564 
565 	if ((status = ntohl(*p++)))
566 		return nfs_stat_to_errno(status);
567 	p = xdr_decode_fhandle(p, res->fh);
568 	xdr_decode_fattr(p, res->fattr);
569 	return 0;
570 }
571 
572 /*
573  * Encode READLINK args
574  */
575 static int
576 nfs_xdr_readlinkargs(struct rpc_rqst *req, __be32 *p, struct nfs_readlinkargs *args)
577 {
578 	struct rpc_auth	*auth = req->rq_task->tk_msg.rpc_cred->cr_auth;
579 	unsigned int replen;
580 
581 	p = xdr_encode_fhandle(p, args->fh);
582 	req->rq_slen = xdr_adjust_iovec(req->rq_svec, p);
583 
584 	/* Inline the page array */
585 	replen = (RPC_REPHDRSIZE + auth->au_rslack + NFS_readlinkres_sz) << 2;
586 	xdr_inline_pages(&req->rq_rcv_buf, replen, args->pages, args->pgbase, args->pglen);
587 	return 0;
588 }
589 
590 /*
591  * Decode READLINK reply
592  */
593 static int
594 nfs_xdr_readlinkres(struct rpc_rqst *req, __be32 *p, void *dummy)
595 {
596 	struct xdr_buf *rcvbuf = &req->rq_rcv_buf;
597 	struct kvec *iov = rcvbuf->head;
598 	size_t hdrlen;
599 	u32 len, recvd;
600 	char	*kaddr;
601 	int	status;
602 
603 	if ((status = ntohl(*p++)))
604 		return nfs_stat_to_errno(status);
605 	/* Convert length of symlink */
606 	len = ntohl(*p++);
607 	if (len >= rcvbuf->page_len) {
608 		dprintk("nfs: server returned giant symlink!\n");
609 		return -ENAMETOOLONG;
610 	}
611 	hdrlen = (u8 *) p - (u8 *) iov->iov_base;
612 	if (iov->iov_len < hdrlen) {
613 		dprintk("NFS: READLINK reply header overflowed:"
614 				"length %Zu > %Zu\n", hdrlen, iov->iov_len);
615 		return -errno_NFSERR_IO;
616 	} else if (iov->iov_len != hdrlen) {
617 		dprintk("NFS: READLINK header is short. iovec will be shifted.\n");
618 		xdr_shift_buf(rcvbuf, iov->iov_len - hdrlen);
619 	}
620 	recvd = req->rq_rcv_buf.len - hdrlen;
621 	if (recvd < len) {
622 		dprintk("NFS: server cheating in readlink reply: "
623 				"count %u > recvd %u\n", len, recvd);
624 		return -EIO;
625 	}
626 
627 	/* NULL terminate the string we got */
628 	kaddr = (char *)kmap_atomic(rcvbuf->pages[0], KM_USER0);
629 	kaddr[len+rcvbuf->page_base] = '\0';
630 	kunmap_atomic(kaddr, KM_USER0);
631 	return 0;
632 }
633 
634 /*
635  * Decode WRITE reply
636  */
637 static int
638 nfs_xdr_writeres(struct rpc_rqst *req, __be32 *p, struct nfs_writeres *res)
639 {
640 	res->verf->committed = NFS_FILE_SYNC;
641 	return nfs_xdr_attrstat(req, p, res->fattr);
642 }
643 
644 /*
645  * Decode STATFS reply
646  */
647 static int
648 nfs_xdr_statfsres(struct rpc_rqst *req, __be32 *p, struct nfs2_fsstat *res)
649 {
650 	int	status;
651 
652 	if ((status = ntohl(*p++)))
653 		return nfs_stat_to_errno(status);
654 
655 	res->tsize  = ntohl(*p++);
656 	res->bsize  = ntohl(*p++);
657 	res->blocks = ntohl(*p++);
658 	res->bfree  = ntohl(*p++);
659 	res->bavail = ntohl(*p++);
660 	return 0;
661 }
662 
663 /*
664  * We need to translate between nfs status return values and
665  * the local errno values which may not be the same.
666  */
667 static struct {
668 	int stat;
669 	int errno;
670 } nfs_errtbl[] = {
671 	{ NFS_OK,		0		},
672 	{ NFSERR_PERM,		-EPERM		},
673 	{ NFSERR_NOENT,		-ENOENT		},
674 	{ NFSERR_IO,		-errno_NFSERR_IO},
675 	{ NFSERR_NXIO,		-ENXIO		},
676 /*	{ NFSERR_EAGAIN,	-EAGAIN		}, */
677 	{ NFSERR_ACCES,		-EACCES		},
678 	{ NFSERR_EXIST,		-EEXIST		},
679 	{ NFSERR_XDEV,		-EXDEV		},
680 	{ NFSERR_NODEV,		-ENODEV		},
681 	{ NFSERR_NOTDIR,	-ENOTDIR	},
682 	{ NFSERR_ISDIR,		-EISDIR		},
683 	{ NFSERR_INVAL,		-EINVAL		},
684 	{ NFSERR_FBIG,		-EFBIG		},
685 	{ NFSERR_NOSPC,		-ENOSPC		},
686 	{ NFSERR_ROFS,		-EROFS		},
687 	{ NFSERR_MLINK,		-EMLINK		},
688 	{ NFSERR_NAMETOOLONG,	-ENAMETOOLONG	},
689 	{ NFSERR_NOTEMPTY,	-ENOTEMPTY	},
690 	{ NFSERR_DQUOT,		-EDQUOT		},
691 	{ NFSERR_STALE,		-ESTALE		},
692 	{ NFSERR_REMOTE,	-EREMOTE	},
693 #ifdef EWFLUSH
694 	{ NFSERR_WFLUSH,	-EWFLUSH	},
695 #endif
696 	{ NFSERR_BADHANDLE,	-EBADHANDLE	},
697 	{ NFSERR_NOT_SYNC,	-ENOTSYNC	},
698 	{ NFSERR_BAD_COOKIE,	-EBADCOOKIE	},
699 	{ NFSERR_NOTSUPP,	-ENOTSUPP	},
700 	{ NFSERR_TOOSMALL,	-ETOOSMALL	},
701 	{ NFSERR_SERVERFAULT,	-EREMOTEIO	},
702 	{ NFSERR_BADTYPE,	-EBADTYPE	},
703 	{ NFSERR_JUKEBOX,	-EJUKEBOX	},
704 	{ -1,			-EIO		}
705 };
706 
707 /*
708  * Convert an NFS error code to a local one.
709  * This one is used jointly by NFSv2 and NFSv3.
710  */
711 int
712 nfs_stat_to_errno(int stat)
713 {
714 	int i;
715 
716 	for (i = 0; nfs_errtbl[i].stat != -1; i++) {
717 		if (nfs_errtbl[i].stat == stat)
718 			return nfs_errtbl[i].errno;
719 	}
720 	dprintk("nfs_stat_to_errno: bad nfs status return value: %d\n", stat);
721 	return nfs_errtbl[i].errno;
722 }
723 
724 #define PROC(proc, argtype, restype, timer)				\
725 [NFSPROC_##proc] = {							\
726 	.p_proc	    =  NFSPROC_##proc,					\
727 	.p_encode   =  (kxdrproc_t) nfs_xdr_##argtype,			\
728 	.p_decode   =  (kxdrproc_t) nfs_xdr_##restype,			\
729 	.p_arglen   =  NFS_##argtype##_sz,				\
730 	.p_replen   =  NFS_##restype##_sz,				\
731 	.p_timer    =  timer,						\
732 	.p_statidx  =  NFSPROC_##proc,					\
733 	.p_name     =  #proc,						\
734 	}
735 struct rpc_procinfo	nfs_procedures[] = {
736     PROC(GETATTR,	fhandle,	attrstat, 1),
737     PROC(SETATTR,	sattrargs,	attrstat, 0),
738     PROC(LOOKUP,	diropargs,	diropres, 2),
739     PROC(READLINK,	readlinkargs,	readlinkres, 3),
740     PROC(READ,		readargs,	readres, 3),
741     PROC(WRITE,		writeargs,	writeres, 4),
742     PROC(CREATE,	createargs,	diropres, 0),
743     PROC(REMOVE,	removeargs,	stat, 0),
744     PROC(RENAME,	renameargs,	stat, 0),
745     PROC(LINK,		linkargs,	stat, 0),
746     PROC(SYMLINK,	symlinkargs,	stat, 0),
747     PROC(MKDIR,		createargs,	diropres, 0),
748     PROC(RMDIR,		diropargs,	stat, 0),
749     PROC(READDIR,	readdirargs,	readdirres, 3),
750     PROC(STATFS,	fhandle,	statfsres, 0),
751 };
752 
753 struct rpc_version		nfs_version2 = {
754 	.number			= 2,
755 	.nrprocs		= ARRAY_SIZE(nfs_procedures),
756 	.procs			= nfs_procedures
757 };
758